Polymers of alkoxystyrenes and block copolymers of alkoxystyrenes and vinyl ethers and processes to prepare these polymers by cationic polymerization are known. For example, Higashimura describes a process for polymerizing vinyl ether and para-methoxystyrenes wherein a catalyst obtained by combining HI and I.sub.2 or ZnX.sub.2 wherein X is a halogen such as iodine, chlorine or bromine is used, Higashimura et al., Macromolecules, Vol. 12, p. 178 (1979). This system is effective in the preparation of these polymers, but the zinc halides are toxic and a process which utilizes a non-toxic catalyst is desirable. The zinc catalysts are also soluble in the polymer solutions and will contaminate the polymer requiring a costly catalyst extraction procedure. Without removing the catalyst the polymer will be highly discolored and the polymer generally has an undersirable color even after catalyst extraction.
The use of zeolites as polymerization catalysts for vinyl ethers is also known. Exemplary processes are described in, for example, U.S. Pat. Nos. 3,228,923; 3,365,433; 3,394,116; 3,461,075; and 3,819,596. Although the mechanism for this polymerization is not clear, it does not appear to be a cationic polymerization. The resultant polymers may have high molecular weights, and have an extremely wide molecular weight distribution. The polymer made by the process of U.S. Pat. No. 3,819,596 is touted as an excellent plasticizer due to the broad molecular weight distribution.
It is therefore an object of this invention to provide a process to polymerize alkoxystyrene wherein a heavy metal cocatalyst is not required. In another aspect it is an object of this invention to provide a process to produce copolymers of alkoxystyrenes and alkenyl ethers wherein a soluble cocatalyst is not required.